The present invention relates to a matrix powder composition for use along with a binder to form a hard composite material. More particularly, the invention pertains to a matrix powder composition for use along with a binder to form a hard composite material wherein the hard composite material exhibits improved erosion resistance while retaining strength. The matrix powder compositions of the present invention may be useful for tools that are involved in any application or operation in which a tool may be subjected to erosive and/or abrasive conditions. Examples include subterranean applications that involve the use of drill bits for drilling a well bore.
Hard composite materials have been formed by incorporating one or more particulate elements within a matrix powder, and then infiltrating the matrix powder with a binder metal to form a composite material with the particulate elements incorporated within. This composite material can be useful in tools or other devices that are subject to erosion. Composite materials may include diamond composites material that can comprise a suitable binder with one or more discrete diamond-based particulate elements held therein. Additional particulate elements that have been used include tungsten carbide. Tungsten carbide can be used in various forms including, but not limited to, microcrystalline tungsten carbide and cast tungsten carbide.
Hard composite materials have been used for a variety of purposes, including the manufacturing of earth-boring drill bits to provide some erosion resistance and improve mechanical strength. For example, polycrystalline diamond compact (“PDC”) cutters are known in the art for use in earth-boring drill bits. Typically, drill bits using PDC cutters include an integral bit body, which may substantially incorporate a hard composite. A plurality of PDC cutters can be mounted along the exterior face of the bit body in extensions of the bit body called “blades.” Each PDC cutter has a portion which typically is brazed in a recess or pocket formed in the blade on the exterior face of the bit body. The PDC cutters are positioned along the leading edges of the bit body blades so that as the bit body is rotated, the PDC cutters engage and drill the earth formation. In use, high forces may be exerted on the PDC cutters, particularly in the forward-to-rear direction. Additionally, the bit and the PDC cutters may be subjected to substantial abrasive and erosive forces.
While steel body bits may have toughness and ductility properties that make them resistant to cracking and failure due to impact forces generated during drilling, steel may be, under certain condition, more susceptible to erosive wear caused by high-velocity drilling fluids and formation fluids that carry abrasive particles, such as sand, rock cuttings, and the like. Generally, steel body bits often may be coated with a more erosion-resistant material, such as tungsten carbide, to improve their erosion resistance. However, tungsten carbide and other erosion-resistant materials are relatively brittle relative to steel. During use, a thin coating of the erosion-resistant material may crack, peel-off or wear, exposing the softer steel body which may then be rapidly eroded. This erosion can lead to loss of cutters as the area around the cutter is eroded away, causing the bit to fail.
Hardfacing is another example where hard composite materials have been used. Hardfacing of metal surfaces and substrates is a technique to minimize or prevent erosion and abrasion of the metal surface or substrate. Hardfacing can be generally defined as applying a layer or layers of hard, abrasion resistant material to a less resistant surface or substrate by plating, welding, spraying or other well known deposition techniques. Hardfacing can be used to extend the service life of drill bits and other downhole tools. Tungsten carbide and its various forms are some of the more widely used hardfacing materials to protect drill bits and other downhole tools associated with drilling and producing oil and gas wells.
Rotary cone drill bits are often used for drilling boreholes for the exploration and production of oil and gas. This type of bit typically employs three rolling cone cutters, also known as rotary cone cutters, rotatably mounted on spindles extending from support arms of the bit. The cutters are mounted on respective spindles that typically extend downwardly and inwardly with respect to the bit axis so that the conical sides of the cutters tend to roll on the bottom of a borehole and contact the formation. For some applications, milled teeth are formed on the cutters to cut and gouge in those areas that engage the bottom and peripheral wall of the borehole during the drilling operation. The service life of milled teeth may be improved by the addition of tungsten carbide particles to hard metal deposits on selected wear areas of the milled teeth by hardfacing.
Current composite materials can suffer from mass or material loss when subject to an abrasive and/or erosive environment. This mass or material loss can lead to tool failure or limited service life of the tool, possibly resulting in non-productive time (NPT). NPT is undesirable. Reducing NPT through extended service life of the tool would be advantageous. As such, it would be desirable to provide an improved hard composite material having improved properties that include impact strength, transverse rupture strength, hardness, abrasion resistance, and erosion resistance.